南大洋海冰影像地图投影变换与瓦片切割应用研究

摘要

南大洋海冰分布是南极考察过程中影响破冰船航行的重要因素,也是南极研究的重要内容之一.目前国际上不同机构发布的南大洋海冰分布图,大多是球面投影,不能直接用于主流的瓦片地图发布.将极方位立体投影海冰图转换为目前主流的网络墨卡托投影地图,并利用合适的图像重采样方法,按照不同级别比例尺进行瓦片切割和编号存储,最终实现海冰影像地图的发布共享是本文的主要研究内容.笔者对不同的图像重采样方法进行了比较,分析了最邻近点采样方法、双线性内插和双三次卷积重采样方法的优劣,针对本文的研究优选双线性内插方法进行影像地图瓦片的切割,并最终叠加融合在Google地图上,实现了Google底图、准实时海冰影像图与破冰船走航位置的集成显示,为雪龙船的冰区航行提供了重要的数据支撑.%The distribution of sea ice over the Antarctic Ocean has a great impact on the navigation of icebreaker ships, and is an important subject of Antarctic research. Maps of sea ice over polar regions released by different international organizations are mostly stereographic projections, which cannot be directly overlaid on Google tile-maps. This paper presents an approach to transform the polar stereographic projection maps into Web Mercator projection maps, which are the most commonly used at present. The study included procedures to incise, number and store the map tiles with appropriate re-sampling algorithms, according to the given scale, and finally release and share the sea ice map tiles. The authors compared different re-sampling algorithms, and analyzed the advantages and weaknesses of Nearest Neighbor Re-sampling, Bilinear Interpolation, and Bicubic interpolation. Over the polar are-a, a Bilinear Interpolation algorithm is recommended to incise map tiles. Finally, sea ice tiles are overlaid on Google Maps in a "XUELONG Online" information platform, integrated with the real-time and historical locations of "XUE LONG" icebreaker. This approach contributes to the navigation of "XUE LONG" across the floating sea ice area. This study provides important information for the identification of icebreaker route selection over sea ice areas, both in Antarctica and the Arctic.